Burglar-alarm.



T. H. FARRELL.

BURGLAR ALARM;

APPLICATION FILED MAR. 11, 1912 1,109,329, Patented Sept. 1. 1914.

%- g @111 7 J m 0 C A] I Z I 2223 rfiqmayf'a f w I w gtmfl I UNITED. F I E [T To all whomit concern Be it known that I, THOMAS Hf FARRELL,

a citizen of the United States, residing at' which is inexpensive and can 'be rea dily attached to a movable object, to give audible signal bysetting a clock movement in motion, when a door or window is opened. The alarm rings a predetermined time and is automatically stopped by a detent; coperating with a disk arranged in the train of the clock movement. The detent normally prevents movement of the clock mechanism by being in engagement with the disk, but when the door or window is opened or moved the detent is oscillated to unlock the disk, and consequently ,allow actuation of the clock movement and the hammer strikes an alarm. After eachrotation .of the disk the detent automatically engages a notch in the disk and stops the rotation thereof and operation of the clock movement.

The novel features of the invention are more fully described in the following specification and claims and illustrated in the accompanying drawing in which: I

Figure 1 represents a 1 front elevation partly in section showing the burglar alarm secured to a door. Fig. 2 is a section taken along the line m m of Fig. 1. Fig. 3i's a per spective detailview of a disk and detent.

In this drawing the latter a designates a,

door and b a jamb. On the inner portion of the door is secured a case 0 to the interior of which is fastened the movement plates d Between these plates is mounted the clock mechanism consisting of a hammer e, jescapement f and a coiled spring 9 having one end fastened to the arbor h and the other end to a post secured to the movement plates. To the arbor h is, fastened thedisk 6 having a notch j with a 'lip 7a formed'by bending one of the side portions of the notch. A detent m is pivotedat n to thecasing. One end of this detent normally engages the notch while the other end is in contact with the tongue 0 of a latch. The latch is fastened to the jamb of the door and the tongue thereof can be retracted, when it is desired to open the door without setting off the alarm. 'Aspring ptends to hold the detent 'into the notch and forces a URGLAaALARM. I p

Specification of Letters Patent. Aflpli'cationiiledl farch 11, 1912 Serial No. 682,937.

Patentedisept. 1,1 14.

the other end of the detent against a stop formed in the casing. A cover is mountj edlonthe outer portion of one of the movement plates. Athumbnut r is; inserted on top of the threaded part of thearbor and serves 'as a'key for winding the spring.

When itis desired to' wind the spring the thumb nut is manipulated to rotate the disk and the lip 7a strikes'on to the detent, thus lifting the end of the detent out of the notch and allowing the disk .to rotate.

When thedoor is opened one end of the detent strikes on to the tongue'o of the latch thus oscillating the detent. to disengage it from the notch j in the disk, the spring then actuates the disk with the clock movement,

and'the hammer e strikes on to the inner wall of the metallic cover q thus ringing an alarm. v

" It will be seen that the disk revolves until the notch reaches the detent, which, autol matically moves into engagement with the notch to lockthe disk and stop the move ment of the clock mechanism.

I claim: 4 I 1. Ina burglar alarm, the combination with a movable and a stationary object, of

a normally wound spring motor mounted on the movable object, a disk provided with a notch and adapted to be rotated by said motor, and means normally engaging said notch and said stationary member, said means being governed by the winding up of I the spring, or actuation of the-movable object torelease said disk to permit the operation' of said motor, said means automatically rengaging said notch [after each rotation. of saiddisk to interrupt the operation of said motor. i

2. In a burglar alarm, the combination with amovable anda stationary object, of a motor including an arbor with a normally wound coiled spring mounted on the mov-.

able object, a disk provided with a notch and secured to said arbor, and means normally engaging said notch and said stationary object, said means being governed by the winding up of thespring or actuation of the movable object to release saiddisk to permit the operation of said'motor, said means automatically re'ngaging said notch after each rotation ofsaid disk to interrupt the operation of said motor.

3. A burglar alarm comprlsing a motor including an arbor with a-spring, a disk mountedon the arbor and operated by the spring, a notch located in the circumference of the disk with a lip formed on one side of the notch, a detent to normally engage the notch and prevent movement of "the said disk adapted to actuate said first inen- I witnesses.

tioned means to release said motor fonwinding, and means secured to said stationary object adapted to release said first-mentioned means upon actuation of said movable object, said first-mentioned means being adapted to automatically reengage sald notch to interrupt the operation of said motor. i

In testimony whereof I have hereunto set my hand in thepresence of two subscribing THOMAS HQFARRELL. Witnesses:

CHRIS. H. ALMSTAEDT,"

H. 'V. McEnRoY.

lcopies ofthis patent may b obtained for five cents each, by addre i g-i1 q gdm bf Patents Washington, I). 0,, a v i; v 

